I've had my Fedex account for 17 years. You create the label, drop off the package and you're done. I don't think I've ever had one opened because I overpack. If you just take it to Fedex without a label, then they'll open it before insurance is approved. That's been going on for years. So you're better off printing your own label from your account, and not showing up with your account # and a package.
This has come about because people were getting lots of insurance for poorly packed shipments, and they had to cover their ass. I had a former RT member (Chad...something or other) ship back speakers that he had Fedex certify because a UPS store packed it. 7 out of the 8 speakers came in with bent frames. He'd used a whopping 1/2" of packing around them and expected them to survive a 2000 mile trip.
Fedex paid his claim, but when they came to inspect at my shop, the inspector said Fedex was had by the UPS owner. That was 7-8 years ago now, and I imagine incidents like that probably helped lead to this new policy.
It's the same old story, one bad apple ruins it for everyone.